Block named on the Balco supply list

Zhanna Block is the latest high-profile athlete to be accused of receiving banned drugs from the same Californian laboratory whose supply of steroids led to Britain's Dwain Chambers being suspended for two years.

Victor Conte, the founder and owner of the Bay Area Laboratory Co-Operative, Balco, in San Francisco, is alleged to have told US government officials that 15 elite athletes received banned substances from him, and the Ukrainian sprinter is reportedly one of them.

Block's name allegedly appears on a list alongside her biggest rival Marion Jones, the American the 31-year-old beat to claim the world 100 metres title in Edmonton two years ago, and Kelli White, who succeeded her as champion in Paris last August.

Other names on the list include Chambers, Tim Montgomery - Jones's boyfriend and world 100m record holder - the former world indoor 1500m champion Regina Jacobs and the twins Alvin and Calvin Harrison, members of the US 4x400m relay squad that won the Olympic gold medal in Sydney four years ago.

The San Jose Mercury News reported that investigators from the Internal Revenue Service compiled the list after Conte had volunteered the names of 27 sportsmen and women - including the baseball stars Barry Bonds, Jason Giambi and Gary Sheffield - to whom he claimed to have supplied steroids.

Conte's lawyers have strongly denied that he supplied banned drugs to anyone and claimed the US government had fabricated his account.

"The coercive nature of that interview as well as the disputed contents of what the agents claim was said in that mysteriously unrecorded statement will be the subject of pre-trial motions," said Conte's lawyers Robert Holley and Troy Ellerman.

Among the claims made in the report by an IRS agent, Jeff Novitzky, and co-signed by a San Mateo County Narcotics Task Force officer, Jon Columbet, Conte is quoted as saying that he supplied athletes with combinations of the previously undetectable steroid tetrahydrogestrinone (THG), a testosterone cream, the blood-boosting drug EPO and modafinil, a drug used to treat the sleep disorder narcolepsy.

The wave of accusations is threatening to drown the sport in the lead-up to the Olympics in Athens later this year and, if substantiated, could deprive the American team of some of its leading medal chances, including Jones and Montgomery.

Under US Anti-Doping Agency rules athletes can be banned from competing even if they have never tested positive. Usada needs only the evidence that perhaps may have been gathered in the Balco case.

The International Association of Athletics Federations could sanction Block under a similar rule. The Guardian tried to contact Block to ask her about the allegations but her husband and agent Mark did not return calls.

UK Athletics is to fine its leading athletes if they do not compete in the Olympic Trials & AAA Championships in Manchester in July. The sport's governing body will dock promotional payments from athletes who attend one of three televised meetings but do not appear in the trials.